I have an older solid state scanning marine VHF radio I'm trying to get going again, after years of non-use.
The mike is missing. These radios all used a simple PTT mike---a common ground, 12+ to one side of the PTT switch, and the audio from one side of the mike element on the other. Three wires total. I'd like to put a plug on a CB mike I have and use that for the marine VHF. I have no manual or schematic, and little chance of finding one (I'm searching).
The chassis mike socket has 5 pins. I can easily find the ground pin. By powering the set up, I can then find the 12v+ pin. That takes care of two of my three wires in the mike cable.
Question being, then, how do I determine which of my remaining 3 pins is for the audio lead?